SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dea34857ffcca1f4b0170d93a63092230e753ac6e980489dd7202d5397c08d25' 
  AND token = 'uBCJaWvncZymcTwBZSpA3U+RRFu/4JhPOXexODChGXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}